1. Field of the Invention
The present invention relates to a storage medium library which can retain a plurality of data storage mediums for storing large amounts of information. It also relates to a storage medium magazine used for such a library.
2. Description of the Related Art
Automated data storage libraries are used for storing and retrieving large amounts of information in digital form. Such a library unit accommodates a plurality of storage mediums and transfers information to and from a selected one of the storage mediums. In the field of data storage libraries, a larger data storage capacity and faster data access capability are in great demand. To satisfy such demands, libraries utilizing optical disks as the storage medium are being developed. Examples of optical disk library are disclosed in JP-A-H11-120668 and JP-A-2001-6258.
An existing optical disk library may incorporate a plurality of optical disks, an accommodation unit for retaining the optical disks, a drive unit for writing data to the disks or retrieving, data from the disks, and a changer unit for moving the disks from the accommodation unit to the drive unit, and vice versa. In such a disk library, each optical disk may be placed onto a tray to be stored in the accommodation unit.
FIGS. 18 and 19 show a tray 91 and an optical disk 92 carried by the tray. Specifically, FIG. 18 is a perspective view showing the tray 91 and the disk 92 (depicted in an exploded manner for better understanding of the structure of the tray 91), while FIG. 19 is a sectional view taken along XIX-XIX line in FIG. 18, with the disk 92 directly supported on the tray 91. The tray 91 includes a disk accommodating space 91a and a circular base 91b. As shown in FIG. 19, the disk 92 is completely received into the space 91a when it is placed on the base 91b. This means that the thickness of the disk 92 is smaller than the depth of the space 91a (and hence the thickness of the tray 91).
In the conventional optical disk library of the above-described type, the storing and the handling of the disk 92 are performed in the state shown in FIG. 19, namely, with the disk 92 received into the space 91a of the tray 91. In this manner, the disk 92 is protected against mechanical damage which would otherwise occur in storing or handling the disk 92. Specifically, when the disks 92 are stored in the accommodation unit, the trays 91 (each carrying one optical disk) are brought into contact with portions of the accommodation unit, while the disks 92 are not. Likewise, when a disk 92 is transferred between the accommodation unit and the disk drive, the disk 92, retreating into the space of the tray, does not come into contact with the changer unit. Accordingly, each disk 92 is not mechanically damaged by the accommodation unit nor the changer unit.
After a tray 91 with a disk 92 carried thereon is transferred to the drive by the changer unit, the disk 92 is separated from the tray 91, to be rotated for recording or retrieving data. To attain this separation, the conventional disk library incorporates a disk-tray separation mechanism for moving the tray 91 downward. Since the disk 92 is held in position by the support of a spindle motor, the disk 92 can be separated from the tray 91 upon actuation of the separation mechanism. This conventional scheme, however, needs the disk-tray separation mechanism to be installed within the library, which is disadvantageous to providing a compact library unit.
Further, the conventional disk library incorporates a accommodation unit for holding a number of trays 91 each having a greater thickness than a disk 92 (FIG. 19). Accordingly, the accommodation unit tends to be rather large. The existence of such a accommodation unit is also disadvantageous to attaining a size reduction of the disk library.